This invention relates generally to automotive vehicle convertible roofs and more particularly to a convertible roof actuation mechanism.
Traditional soft-top convertible roofs for automotive vehicles typically employ four or five roof bows, having an inverted U-shape, spanning transversely across the vehicle for supporting a vinyl, canvas or polyester fiber pliable roof cover. The number one roof bow is mounted to a pair of front roof rails and is typically latched to a stationary front header panel of the automotive vehicle body disposed above a windshield. A number two roof bow is typically mounted to a pair of center roof rails which are pivotably coupled to the front roof rails. Furthermore, the number three, four and optional five roof bows are commonly mounted to a pair of rear roof rails which are pivotably coupled to the center roof rails. For example, reference should be made to U.S. Pat. Nos. 5,338,085 entitled "Folding Top for Motor Vehicles" which issued to Guckel et al. on Aug. 16, 1994; 5,225,747 entitled "Single-Button Actuated Self-Correcting Automatic Convertible Top" which issued to Helms et al. on Jul. 6, 1993; 5,161,852 entitled "Convertible Top with Improved Geometry" which issued to Alexander et al. on Nov. 10, 1992; 4,948,194 entitled "Flexible Roof for a Convertible Motor Vehicle, Provided with a Safety Hook for the Rear Arch of the Roof Frame" which issued to Dogliani on Aug. 14, 1990; 4,720,133 entitled "Convertible Top Structure" which issued to Alexander et al. on Jan. 19, 1988; 4,537,440 entitled "Vehicle with a Convertible Top" which issued to Brockway et al. on Aug. 27, 1985; and 2,580,486 entitled "Collapsible Top for Vehicles" which issued to Vigmostad on Jan. 1, 1952.
Traditional soft-top convertible roofs possess an inherent drift problem. In other words, when the convertible roof is moved to its fully raised position, the forwardmost or number one roof bow is positioned against the front header panel for subsequent latching. However, the stretched fabric cover acts to pull the number one roof bow in an unintended and undesired rearward direction such that it drifts away from the front header. This drifting situation is especially apparent in new convertible roofs. Accordingly, the vehicle occupant must then physically pull down upon a handle attached to the number one roof bow and hold it against the front header panel for subsequent latching. This manual action presents a crude and unrefined operational perception. This drifting problem is also present between a rearmost or number five roof bow and an adjacent tonneau cover. The number five roof bow and attached rear edge of the cover are often raised to an upward position by separate actuators while the tonneau cover is returned from a substantially vertical position to a substantially horizontal position; the number five roof bow is then pivoted to its lowered position against an upper surface of the tonneau cover for latching thereto. However, the stretched fabric covering tends to pull the number five roof bow in a forward manner thereby causing it to drift away from the tonneau cover. This situation is inconvenient to remedy due to the difficulty of an occupant accessing this rear area when seated in the front seat.
Notwithstanding, U.S. Pat. No. 5,385,381 entitled "Vehicle Roofs," which issued to Moore et al. on Jan. 31, 1995, employs a moving number four roof bow to tension a fabric cover. However, this patent discloses directly attaching each leg of the number four roof bow to a corresponding main balance link. Furthermore, a first gas strut acts between the number four roof bow and the balance link while a second hydraulic ram, per side of vehicle, moves the number four roof bow through a clevis and pin arrangement.
In accordance with the present invention, the preferred embodiment of a convertible roof actuation mechanism includes a pliable roof cover, a top stack mechanism supporting the roof cover, and at least one roof bow of the top stack mechanism independently movable relative to the remainder of the top stack mechanism for selectively reducing and increasing tension of the roof cover during latching. Another aspect of the present invention provides a single driving mechanism, such as a piston, for each side of the vehicle, to operate both the tension relieving roof bow movement and the top stack mechanism movement. In a further aspect of the present invention, a rigid backlite is attached to a pliable roof cover. Still another aspect of the present invention provides a more compact and reliable roof bow locking mechanism and linkage arrangement. Yet another aspect of the present invention employs multiple links and a connector to couple an optional number five roof bow to a number four roof bow for simultaneously moving the numbers four and five roof bows to tighten or loosen the fabric roof.
The convertible roof actuation mechanism of the present invention is advantageous over conventional devices in that the present invention reduces drifting of the raised convertible roof away from the front header panel and, alternately a tonneau cover, by selectively reducing and then increasing tension or tautness of the roof cover. Furthermore, packaging space of the stowed convertible roof is optimized in the storage compartment by the linkage movement of a number four roof bow; this allows for placement of a very large and rigid backlite in a relatively small storage compartment, thereby avoiding the creasing and discoloration disadvantages commonly associated with folded flexible backfires made of plastic. The present invention is also advantageously employed in combination with stationary affixation of the rear edge of the roof cover to the body where front header panel latching drift and tension problems are often exacerbated. Moreover, the single driving mechanism, per side of vehicle, used for operating the tension reducing roof bow and the top stack mechanism is much more cost effective and less failure prone as compared to a more complicated, traditional two pistons/rams per vehicle side. Additional advantages and features of the present invention will become apparent from the following description and appended claims, taken in conjunction with the accompanying drawings.